Even if there is only one possible unified theory, it is just a set of rules and equations. What is it that breathes fire into the equations and makes a universe for them to describe?

The usual approach of science of constructing a mathematical model cannot answer the questions of why there should be a universe for the model to describe. Why does the universe go to all the bother of existing?

There are grounds for cautious optimism that we may now be near the end ofthe search for the ultimate laws of nature.

Stephen Hawking Quotes